Juan Martin del Potro (r.) of Argentina holds the champions trophy after defeating Roger Federer of Switzerland in the men's singles final match at the US Open tennis championship in New York, September 14.

What Williams unleashed on a lineswoman who called her for a foot fault in the decisive game of her semifinal match was primal. The lineswoman scurried to the chair umpire for safety. Meteorologists might have been inclined to place Flushing Meadows under a severe storm warning for the space of 20 Saturday evening seconds, so raw and powerful were her emotions.

Federer being Federer, he managed to swear with no small amount of panache. He was angry, no doubt. Yet behind his Swiss stoicism exists the smallest trace of the diva – a man irked by the things that dare to defy him, be they shot spot technology, hooting New Yorkers, or a chair umpire with the gall to tell him to be quiet.

As a result, his fit of rage was less a malediction worthy of the Furies than a fit of pique more suited to the salons of Paris.

Federer was imperious in his disdain, utterly dismissive of chair umpire's authority. Tilted back in his chair, spouting off expletives to the night air, he might just have well been a beret-coiffed restaurant critic sending back a platter of moldy brie.

It was not the most admirable show of sportsmanship. But it was theater – and not a horror film, as had been the case the night before.

Federer has, to some degree, won the right to be right about almost everything by generally being right about almost everything. His dislike of the video-challenge system is deep and predates Monday night. While most players accept overruled video challenges with a resigned shrug, he attempts to argue with the computer, pointing to the spot that it clearly misread.

He is not accustomed to losing, even to IBM's indefatigable strings of ones and zeroes.

In theory, that is Mr. del Potro's right. But if a player wants to challenge a point, the rules say he must do it immediately. Del Potro could have taken a subway to Barnes and Noble and read the first three chapters of "The Lost Symbol" in the time it took him to decide whether to challenge.

By the time he did, both players were actually off the court for the between-game break. Yet Garner accepted the challenge.

Neither Williams nor Federer will look back on their outburst with pride, surely. But Williams's outburst will surely go down as one of the epic tennis meltdowns of all time, and not just because she is a woman.

Federer's? Even amid the expletives, it was so urbane, that one sense he only left one thing off: "QED."